Stentless Braided Support Structure for Minimizing Emboli
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Solution Overview
Problem
Percutaneous valve replacement methods face challenges such as difficulty in preventing leakage, stent-related emboli, non-conformity to native lumen, tradeoff between strength and compressibility, irretrievability, and increased delivery size, which complicate the procedure and patient recovery.
Innovation Solution
A stentless tubular mesh support structure made of braided shape-memory strands that can be delivered through a small catheter, gradually expands to conform to the lumen, traps emboli, and can be retracted for repositioning, allowing for a smaller delivery size and reduced trauma.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a stent is used as support scaffolding for the prosthetic valve, then structural support is provided, but emboli are created during expansion
Solution Approach 1:
The patent removes the stent component from the prosthetic valve assembly entirely. The support structure is replaced by the valve frame itself, which provides structural support without the emboli-generating expansion characteristics of stents. This extraction of the problematic stent element while retaining the necessary support function directly resolves the contradiction between structural support and emboli generation.
2Strength
If a stent is used to house the prosthetic valve, then support is provided, but paravalvular leakage occurs due to non-conformity to native lumen
Solution Approach 1:
Instead of forcing a rigid stent to conform to the native lumen, the patent inverts the approach by designing a flexible valve frame that adapts to the lumen geometry. The frame is constructed to be compliant and conformable to the native valve annulus shape, allowing it to seal effectively against the lumen wall while providing structural support. This inversion from rigid-to-flexible support resolves the contradiction between support strength and sealing effectiveness.
3Strength
If a stent is used for valve support, then structural integrity is maintained, but the device cannot be retrieved once deployed
Solution Approach 1:
The patent employs a dynamic frame structure that transitions from a compressed delivery state to an expanded deployed state. The frame is designed with memory properties that allow it to be compressed for delivery through a catheter, then expand to provide structural support. Crucially, the deployment mechanism allows for controlled expansion and potential re-compression, enabling retrieval or repositioning if needed. This dynamic design resolves the contradiction between maintaining structural integrity and enabling retrievability.
4Strength
If the valve is mounted on a stent, then support is provided, but the collapsed diameter increases requiring larger catheter caliber
Solution Approach 1:
The patent integrates the support function directly into the valve frame structure itself, eliminating the need for a separate stent. The frame is designed with self-supporting characteristics that allow it to maintain structural integrity while in a highly compressed state within the delivery catheter. By nesting the support function within the valve structure rather than adding a separate stent layer, the collapsed diameter is minimized while still providing adequate support during and after deployment.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively minimizes emboli generation, prevents paravalvular leakage, achieves strong support without increasing delivery size, and allows for precise placement and repositioning of the prosthetic valve, enhancing procedural safety and patient recovery.
Implementation Method 1
The tubular mesh is formed one or more fine strands braided together into an elongate tube. The strands may be fibrous, non-fibrous, multifilament, or monofilament. The strands exhibit shape memory such that the elongate tube may be formed into a desired folded shape, then stretched out into a very small diameter, elongated configuration.
Implementation Method 2
The strands exhibit shape memory such that the elongate tube may be formed into a desired folded shape, then stretched out into a very small diameter, elongated configuration. Upon deployment, the elongated tube is slowly pushed out of the delivery catheter, where it gradually regains its folded, constructed configuration. The braid effectively traps all emboli that may be released from the vessel walls.
Data Source
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AI summary
A stentless support structure capable of being at least partly assembled in situ. The support structure comprises a braided tube that is very flexible and, when elongated, becomes very long and very small in diameter, thereby being capable of placement within a small diameter catheter. The support structure is preferably constructed of one or more thin strands of a super-elastic or shape memory material such as Nitinol. When released from the catheter, the support structure folds itself into a longitudinally compact configuration. The support structure thus gains significant strength as the number of folds increase. This radial strength obviates the need for a support stent. The support structure may include attachment points for a prosthetic valve.